It is generally known that camshaft adjusters enable optimal valve control times over a broad load and rotational rate range for a motor. In this manner, significant reductions in emissions and fuel consumption have been achieved. Furthermore, by optimizing the torque and the performance, the driving enjoyment is increased significantly. A distinction is made in the prior art between electric camshaft adjusters and the hydraulic camshaft adjusters specified in the introduction.
Rotors are known from the field of hydraulic camshaft adjusters, which are composed of a first rotor element and a second rotor element. This is disclosed, for example, in the German patent application DE 10 2009 053 600 A1. Two rotor elements are connected with pins or sintered therein. The disadvantage with this is that additional connecting parts such as pins are required. As a result, there are additional costs for parts and installation.
Another embodiment for joining two rotor elements of a rotor is described in the German patent application DE 10 2008 028 640 A1. Two rotor elements are designed therein, such that they can be joined due to their respective “distinct” geometries. Two rotor elements that seal oil channels through sinter facets, and are thus connected to one another, is disclosed in the German patent application DE 10 2011 117 856 A1. The European patent application EP 2 300 693 B1 furthermore describes two identical rotor elements, joined by means of a form fit and press fit to form the oil channels. In the documents specified in this paragraph, the form-fitting and sealing elements extend beyond sealing surfaces, and can be produced either by additional separating planes in the sintering tool or by an excess pressure applied to the entire surface of the flange on the rotor elements. The negative consequences here are the additional tool costs, larger pressing machines and a reduction in quality of the sealing surfaces in the interstice subjected to excess pressure, e.g. the degradation of the evenness and parallel alignment of the end surfaces of the rotor, and an increase in the internal leakage between the oil channels as a result of irregularities in the interstice.
The rotor designed in the form of a composite system, wherein the rotor core plus the cover form the oil channels, is disclosed in the European patent application EP 1 731 722 B1. The separating plane is not in the sintered part thereby, because the complete width of the rotor is produced using sintering technology, as is the case with the single-piece rotors known from the prior art. As a result, it is not possible to obtain a cost reduction in relation to a single-piece rotor, because a larger compression machine having a higher pressure force must be used, as is the case with a single-piece rotor. A cost reduction first obtained by reducing the width of the rotor, e.g. by means of the division of the rotor described in the introduction, can be realized as a result of lower cost factors for the smaller compression machine.
One objective of the present disclosure is thus to further develop a hydraulic camshaft adjuster, having an at least two-piece rotor, such that it is constructed in a cost-effective manner, with higher quality, and is furthermore functionally reliable when in operation.
This objective is achieved by means of a hydraulic camshaft adjuster having an at least two-piece rotor, comprising the features described herein.
Another objective of the present disclosure is to create an at least two-piece rotor for a hydraulic camshaft adjustor, that is produced simply and economically.
This objective is achieved by means of an at least two-piece rotor for a hydraulic camshaft adjuster comprising the features of described herein.
Another objective of the present disclosure is to provide a simple, quality-improving and economical method for producing a rotor for a hydraulic camshaft adjuster.
This objective is achieved by means of a method for producing a rotor for a hydraulic camshaft adjuster comprising the features described herein.